Heat exchanger



K. G. AHLEN HEAT EXCHANGER Feb. 24, 1959 4 Sheets-Sheet 1 Filed May 16,1951 a k w lNgENTQR.

ATTORNEY eb. 24,- 1959 V K. G. AHLEN Filed May' 16, 1951 HEAT EXCHANGER4 Sheets-Sheet 2 Fig.5.

' v I IgVENTO ,MJK

A TTORNEY Fig.9.

- HEAT EXCHANGER Filed May 16, 1951 Y 4 Sheets-Sheet s 106 1 11a 104 Hom 1 4 358 106 1 110 Fig.11.

a INVENTOR.

ATTORNEY Feb. 24, 1959 I G. AHL-EN HEAT EXCHANGER Filed May 16, 1951 4Sheets-Shegt 4 771 III a IN V EN TOR. a fls l, .f

mnN

A TTORNEY United States Patent HEAT EXCHANGER Karl Gustav Ahln,Stockholm, Sweden, assignor .to Svenska Rotor Maskiner Aktiebolag,Necka, Sweden, a corporation of Sweden Application May 16, 1951, SerialNo. 226,582

Claims. (Cl; 257-=-241) The present inventionrelates to heatxtransfer"and-in its broader aspects has reference toheat transfer between ,heat.exchange at high rates of transfer per unit area' of heat exchangingsurface, to provide forsuch transfer with minimum expenditure of powerfor eflecting relative movement between the heat exchanging bodies andin certain of. its aspects to utilize movement of the solid heatexchanging body to create, in whole or ,in part, there- I quired flow ofthe fluid or fluids with which the solid body is inheat exchangerelation.

In order to attain the above generally stated objects and other and moredetailed objects hereinafter appear- .ing, the invention contemplatesthe provision of Qrotating solid body in the form of a rotor having amultiplicity of circular fins or ribs with intervening channels inthe-form of grooves concentric with the axis of rotation of the rotor, withwhich'there is associated a rotationally stationary structure havingbafile members projecting into the grooves and cover means for. thegrooves for controlling flow of fluid in the grooves, such structurefurther being combined with means providing transfer passages forconducting fluid to and from diflerent grooves inac- 'cordance withnovel principles hereinafter more fully described, which result in anovel character of flow which is productive of the improved resultssought by the invention.

The invention is particularly adapted for heat exchange between twogaseousfiuids'for purposes such as-the pre- .heating of air to be usedfor combustion, by waste heat extracted from combustion-gases exhaustedfrom; apparatus such as power boilers and internal combustion enginesand-gas turbines. The invention will therefore be described hereinafter,by wayof example but Without limitation, as applied to air preheatingstructure, but it will be understood that the principles of theinvention are susceptible of use in many other applications andthat forcertain of such applications, the principles of the inven* tion in itsbroader aspects may be carriedout with only certain features of thestructure hereinafter .describedin connection with the air preheaterapparatus chosen by way of example. I

For a better understanding of the more detailed nature of the invention,the manner in which it maybe carried into practical effect, and theadvantages to be derived from its use, reference may best be had totheensuing portion of this specification, taken in conjunction with theaccompanying drawings forminga part hereof, inwhich:

Fig.1 is a more or less diagrammatic longitudinal secof member 30.

"ice

tion, online 1--1 of Fig. 2, ofan air preheatingapparatus embodyingtheprinciples ofthe invention;

Fig. '2, and-with certain elements indicatedlinjphantom for the sake ofclarity;

Fig. 4 is a fragmentary perspective view of part of the structure shownin the precedingzfigures and with certain elements omitted for the sakeof clarity;

Fig. 5 is a view, similar to' Fig. 3, showing a different structuralarrangement of certain of the parts. for producing. an. alteredcharacter of. fluid flow;

Fig. 6 is afragmentary crosssection taken on the line 6-6 of Fig. 5;

Fig. 7 is .afragmentary; perspective view, similar to Fig. 4, of thearrangement shown in Fig 5;

Fig. 8 is a view similar to Figs. 3 and. 5 showing an other arrangementof structure for producing fluid flow of different character than thatshown in Figs. 3 and 5;

Fig. 9 is a fragmentary cross section taken on line 99 ofFig. 8;

Fig.. 10' is a. fragmentary longitudinal. section. taken on line10--.-10 of Fig. 8; I

Figill'is a view, similar to Fig. 8, showing structure providing analtered character'of fluid flow as compared with that of Fig. 8;

Fig. 12 is a longitudinal.sectionsimilar to'. Fig. lshowing apparatusembodyingthe invention arid having adifplicity of external axiallyspacedv radialifins or ribs 22,

providing between them a multiplicity of external annular channels orgrooves 24. The drum further carries'a multiplicity of similar internalribs 26 providing a multiplicity of internal annular grooves 28.

Associated with the rotor there is provided a rotationally stationarys'tructure comprising a' hollow drumlike internal casingmemberindicate'd generally at 30. Member '30 is mounted"coaxiallywiththe' rotor and has a cylindrical casing wall 32 radiallyspaced'from the inner ends of the internal ribs26. "It further isprovided with an inlet 34 at one end and outlets 36 at the other end.

The stationary structure further comprises an outer drumlike casing'wall38surrounding the rotor'and radially spaced from the external ribs 22. iThe stationary structure further has end walls 40 and 42,-the formerextending inwardly past the end wall 16 offtherotor to shaft part 12 ofthe rotor where aseal 41may' be employed, and the latter extendinginwardly to the inlet portion 34 An inlet duct 44; for fluidcommunicates by way of opening 46' at one end of the rotor withthe space48 between rotor wall 18 and the outer casing 38. This spacecommunicates 'at'the other end of the rotor by way-of an opening 4? withthe outlets 50 'and 52.

The wall'54 extends inwardly to a seal diagrammatically indicated at '56and with wall 42 providing an outlet duct ber30 through theinlet 34 andnows in'the direction of arrows 62 through member30. From thisspace'the'air flows -generallyfrom right to left as vie'wedinFig-l,

add-ih -amanner hereinafter described more in detail,

through the space 60 between the rotor drum l8 -and similar to passage86.

differ in that they are oblique in opposite directions with M wer A,

i F I 3 the wall 32 of member 30, and from this space to the outlet duct58.

Hot fluid, such as spent combustion gases, enters in the directionindicated by arrow 64 through inlet duct 44 and opening 46 to the space48 between the rotor drum 18 and the outer casing Wall 33. The gas flowsgenerally from left to right as viewed in Fig. 1 through this space in amanner hereinafter to be described and through opening 50 to the outletduct 52.

The wall 32 of member 30 carries a plurality of battle members 66extending axially of the rotor and peripherally spaced around thecircumference of wall 32.

These members are of comb-like form having a multip- I licity of fingers68 projecting into and substantially filling the cross sections of thegrooves 28. Similar comb-like bafile members 70 extend inwardly from theouter casing wall 38 and are provided with fingers 72 substantiallyfilling the cross sections of the external rotor grooves 24.

Externally of the ribs 22 and located peripherally in spaced relationbetween the battle members 70, a plurality of cover members 74 extendaxially in closely spaced relation to the crests of the ribs 22. Thesecover members are supported by means of partition or guide plates 76carried by the casing wall 38, as will be more clearly seen from Fig. 3.These partitions extend peripherally from one baffle 70 to the next andcomprise oblique central portions 78 overlying the cover members 74 andtransverse end portions 80. The end portions 80 of these partitionsextend beyond the edges of the cover members to the adjacent baflles anddivide the spaces between the edges of the cover plates and the bafflesinto two series of axially aligned ports between each two adjacentbafiles. One series of such ports is indicated at 82, 82a, 82b and 82c,and the other is indicated at 84, 84a, 84b and 840, in Figs. 3 and 4.These ports provide communication between the sectors of the grooves 24between the adjacent battles and the space between the bafiles whichlies radially outside the cover 'members or plates 74, the latter spacebeing divided by the partitions into a series of oblique transferpassages as indicated at 86, 86a, 86b and 860 in Figs. 3 and 4,

these passages being defined bythe cover plate '74, the l radially outerparts of bafiles 70, the outer casing wall 38 and the partitions 76.

Radially inside the rotor drum 18, a similar structure is providedcomprising cover plates 88 disposed adjacent to the crests of the innerribs 26 and series of partitions or guide plates 90 for supporting thecover plates and forming series of ports 92'and 94, and together withthe cover plates 88, the inner casing wall 32 and adjacent inner bafiles66 providing oblique transfer passages 96 Transfer passages 86 and 96respect to the rotor axis.

The operation of the apparatus described is as follows:

Considering first the gas entering through duct 44 and opening 46, thisgas enters radially a group of grooves 24 through inlet ports 82distributed around the periphery of the structure. It being assumed thatthe rotor is turning in the direction indicated by arrow 98 in Fig. 4,friction between the gas and the surface of the moving ribs causes thegas streams in the grooves to move pcripherally in the direction ofrotation of the rotor under the cover plate 74 until they are forcedradially out of 1 the grooves by the fingers 72 of the bafile members70, which substantially block or dam the grooves.

If we now consider the action of the gas streams in the portionof theapparatus shown in Fig. 3, it will be apparent that the streams enteringthe grooves through streams flow until'ejected-through port 84a intotransfer passage 86b which carries the air to the inlet port 8211*bylthe relatively dirty combustion gases.

of a succeeding set of grooves. This action is repeated until the gasreaches the discharge end of the rotor and from Fig. 4 it will beevident that the gas column entering port 82, which is divided intoindividual streams in the grooves, travels in what may be said to be agenerally helical path to flow along the rotor between two adjacentbatlies. From the preceding description, it will be obvious thatperipherally of the rotor there will be a series of such gas columnseach confined between two adjacent bafiies and moving in generallyhelical paths along the rotor.

The action with respect to flow through the grooves between the innerflanges 26 is the same as being described and for the apparatus assumed,theair enters through duct 34 and is divided into a number of aircolumns each flowing between adjacent baffles in a generally helicalpath along the rotor to the outlet duct 58 While both the gas and theair flow peripherally in the direction of the rotor, while in thegrooves, it will be evident from Fig. 1 that the general flow relationbetween the two fluids is counterflow, the hottest gas being in heatexchange relation with that part of the rotor in contact with thehottest air and the coolest gas being in heat exchange relation withthat part of the rotor to which the coolest entering air is admitted.

The action of the apparatus has been described above as applied to thepreheating of combustion air by combustion gases and in suchapplications it is ordinarily preferable to pass the gases through theexternal grooves of the drums and the air through the internal groovessince the volume of gas passing through the apparatus in suchapplications is usually larger than the volume of air. Also, theexternal groove structure is more readily cleaned of solids such as sootand ash deposited Insofar as the basic operation is concerned, it will,however, be evident that if desired the hot medium may be passed throughthe internal grooves, and the medium to be heated passed through theexternal grooves, the choice being governed by the nature andcharacteristics of the media employed and the desired heat exchangebetween tained. Also, by limiting the uninterrupted flow of the fluidsin individual grooves to sectors of predetermined length, the characterof the flow can be controlled so as to produce a high rate of heattransfer not only because of high relative velocity, but also because ofthe fact that the absolute velocity of the fluid can be maintained at asufiiciently low value to prevent turbulence of an undesired nature. Ifthe velocity is sufliciently low, generally laminar flow can bemaintained except at the surface layers where small secondary eddiesrotating about axes normal to the general line of flow are produced.These eddies are desirable from the standpoint of heat transfer and donot create much resistance to flow, and since the grooves are preferablygenerally relatively deep and narrow, the eddy like turbulence of thesurface layers is sufficient to bring most of the fiuid the rate of heattransfer accordingly reduced, but also there may be induced a rotaryturbulence in the plane of rotation, which is undesirable. Further, byejecting the fluid from the grooves after a predetermined length oftravel and transferring the fluid to another set of grooves, it isfurther ensured that all of the fluid in a t given stream or ct-numb isbrought into intimate heat exchange relation with heat transfer surfce.The number, spacing and cross sectional shape and area of the groovesmay vary widely depending upon the nature of the heat exchangeconditions to be met, the character of the fluid or fluids involved,entering temperatures and desired leaving temperatures, volumes to behandled, pressures and other specific factors. These factors will alsoaifect the length of the paths of flow of the streams in individualgrooves, the grouping of the grams, which may, for example be such in anextreme ease, that each group may consist of but a single groove. In theembodiment being described the grooves have, for the sake of simplicity,been shown of equal cross section between equally spaced ribs. It willbe evident, however,

that in cases where a gas is materially cooled and contraots materiallyduring its flow through the apparatus, and it is desired to maintain arelatively constant velocity of flow, the ribs may be spaced closertogether at the colder end than at. the hot end to compensate for thecontraction. 7 h v Also, in apparatus where the path of flowisrelatively long and through a large number of groove sectors, thecumulative eitect of the friction may result in a higher than desiredvelocity through the apparatus when n a given fluid column travels inall cases through the grooves in the direction ofmovement of the rotor,as illustrated for xample" in Fig. 4. This condition can readily beavoided by apparatus operative to reverse the direction of flow in anyselected number of sectors'so that in such sectors the fluid now in thegrooves is counter to the direction of movement of the rotor andginFigs. 5 to 7, one suitable embodiment of apparatus for effecting thisis'illustrated. In substantially allparticulars the arrangement is thesame as that previously described and cor responding parts arecorrespondingly numbered. The difference between the constructions isthat for any se lectedspace, or spaces, as shown more particularly inFigs. 5 and 7, the direction of slant of the oblique por: tion 78 of thepartition members 76 is reversed as indicated at7$riso that if wecompare Figs. 3 and 5, and Figs. 4 and 7, respectively; it will be seenthat the fluid flowing from the grooves through outlet port 84a, flowsaxially in the arrangementof Figs. 5 and 7 to inlet port 82b, which isin effect an axial continuation of the outlet port 84a. From inlet port82b, the fluid flows through the grooves counter to the direction ofrotor movement to outlet port 8412 which in this embodiment is on thesame side of the cover member 74 as the inlet ports 82 and 82a. In theembodiment illustrated, the counter flow is carried through a pluralityof groups. of grooves-,.

hut it will be evident that this specificarrangement may be varied atwill with respect to the number and arrangemeat of passes through thegrooves in which the fluid flows counter to the directionnof rotorrotation, as come pared with the passes in which the flow is in the samedirection. In any case, it will be apparent that in those passes wherethe fiowis counter, to the direction of rotor rotation, friction willexert a decelerating effect and by proper selection for a given designthe rate of flow of fluid through theapparatus as a whole may readily begoverned to suit the specific conditions. I n H n e .As noted above, thegrooves are preferably relatively deep and narrow and the ratio of depthto width of the grooves may in many, instances be, as much as tengtoone, or even materially greater. With such relatively deep and narrow.grooves, thejrate of heat transfer in the grooves is improved by theprovision of auxiliary guide fingers shown at 102 and .104 in Fig. 2,which fingers extend only partially oi the full depth of the groovesandare located so that they serve to divide and guide the fluid enteringand leaving the groove sectors through the respective. inlet and outletports. These fingers may beparts er saint, like member similar a; theberfle menses 70 aaaslrpporteatn anysui tablefashidn semis 6 as parish:the siatieaary lsfrncfiire, it being noted that in the presentembodiment these guide members rnust be radially spaced m thecylindrical walls 32 an as re; spectively, of the stationary structuresince the fluid must flow" across the tops of these guide members :inits flow' between the several ports and the transfer passages. For thesake of clarity, these guide members have been shown, in phantom viewinFig. 3 and have been omitted from the showing in Fig. 4 The number andspecific arrangements of the guide fingers at any particular port orseries of ports may be varied to suit the individual conditions requiredin order to obtain a more advan tageous distribution of flow of thefluid throughout the a depth or the groove. l v

Also in certain instances it may be desirable to provide inlet ports ofgreater peripheral extent than that of theoiitlet ports, rather thanports of equal area as shown in the apparatus illustrated. n e

It will further be apparent from the nature of the ap paratusfdescribedthat in addition to acting as a heat exchanger the apparatus may alsoprovide all of the power required to create the flow of the fluid mediaand for example when used as an air preheater may provide the only meansrequired to produce the necessary forced draftflow of the combustion airand also the force required to exhaust the spent combustion gases".Thii's th apparatus may enable separate forced draft and exhaust fans tobe eliminated entirely, or 'meterially reduce the power requirements'for such fans by acting as a compound "fan for both purposes. v

V Inboth of the embodiments above described, the stationarystrlicture isarranged so that the fluid columns flow in generan' axialdirectionfromendto endof the rotors. This arrangement, however, may bevaried and in rigs; s to 10, another embodiment is'illustrated in whicha different path of flow -forthe air columns is provided. In thisexample, the general arrangement of rotor and stationary structure areas shown in Fig. 1, and corresponding parts are similarly designated. Inthe present construction, the bafiie members providing the fingersextending into the grooves, do not extend from end to end of the rotorbut are peripherally offset as indicated at 7021-, 7%, 700-, 7021 and ain Fig. '8. Each of these offset bafiles is coextensive with a group ofgrooves, the number of which may be chosen at Will, axially coextensivewith the baffles. A series .of sets of box like cover members 106 and108, the botto'rns'of which provide respectively the cover members 74and SSlocated respectivelyover the inner and outer rotor grooves. Theend walls 110 and 112 of these box like rnernbers define peripherallythe limits of the inlet outlet ports communicating with the groovesectors while tite -side walls 1'14'and 11 6 define the aXial extent orports. Due to "the peripherally oflset relation *or adjacent ones ofthefseveral series of the box members "the outlet sns'cdmmunicae withone 'group of grooves which are axially in communicati n jwith the inletports or the next adjacent group ofg'rdoves by way of axially extendingtransfer passages 118, each defined by a bathe member, the'side walls oftwo of the adjacent box mem bers, and theinner or outer casing wall 32or 38 as the case may be.

-FrornFifg. 8, the natu're of the flow of the fluid colurnns isindicated by arrows 120, -frdm which it will be seen that the severalcolumns progress successively 'tlirdugh peripherally ofis'et sectors ofaxiallysuccess'ive groups of groans, the general direction of the pathof 'flow 'bein'g" helical around the rotor drum rather thangenennyyaiauy thereof, as in the arrangement shown in Fig. 1.

1 "In the present arrangement, auxiliary. guide fingers 10': end 104 areshdw'nand it win be noted that in the present construction these guidefingers can be extended support by the casing parts 38 and 32,respectively,

sinee the fl ow through the transfer passage is lengthwise of theseguide members rather than across the tops of them, as in the previouslydescribed embodiments.

In the arrangement shown in Fig. 8, the fluid flow iii the grooves isalways in the direction of movement of the rotor and for reasonspreviously explained it may be desirable to provide for counter flow ofthe fluid in one or more groups of grooves. An arrangement for effectingthis is shown in Fig. 11, wherein certain of the baflie members 70 andbox members 106 are shown in offset relation such that the direction offlow of the fluid columns is peripherally reversed as indicated byarrows 122.

In Figs. 12 and 13, the invention is shown embodied in a rotor ofdifferent form than that shown in the previously described embodiments.

In this form of the apparatus the rotor shaft 200 carries a radiallyextending disc 202 which in turns supports a multiplicity of radiallyspaced concentric cylindrical ribs 204 and 206 on the opposite sides ofthe disc respectively and providing a multiplicity of annularcylindrical channels of groove like form 208 and 210, respectively. Thestationary structure indicated at 212 comprises an outer cylindricalshell 214 between which and disc 202 a seal diagrammatically indicatedat 216 is provided, and end walls 218 and 220. The structure forms aninlet duct 222 for fluid such as air to be heated, which communicateswith the annular space 224 immediately around the rotorshaft on one sideof the disc 202. The structure further provides an outlet duct 226having an annular portion 228 extending around the periphery of thecasing adjacent to the end wall 220 and the flow of-air from duct 222 to226 is generally outward from the central inlet space 224 to theperiphery of the rotor duct and the annular duct 228. The end wall 220carries a plurality of sets of bafile members 230 which provide fingers232 extending into and substantially damming the grooves 208, the setsof baflles at the same radius being peripherally offset with respect toadjacent sets of baflles at greater radius, as seen more clearly in Fig.13, and between adjacent baflles of each set are box like cover members234 which are likewise in sets, with adjacent sets of different radiusperipherally offset relative to each other.

These cover members 234 are similar in form and function to the box likecover members illustrated in Fig. 8, and have side walls defining inletand outlet ports 236 and 238 communicating with the sectors of thegrooves between adjacent baffles of the same set. As further will'beseen from Fig. 13, the relative periphcral location of the cover membersof the adjacent sets is such that the inlet ports leading to one groupof grooves'is radially in registry with a group of outlet ports leadingfrom a radially adjacent set of grooves, to provide radially extendingtransfer passages 240 for carrying fluid discharged from the sectors ofone group of grooves to peripherally offset sectors of the adjacentgroup of grooves lying radially outside the group from which the fluidis discharged.

By comparison of Figs. 13 and 8, it will be evident that the arrangementis the same in principle in both, the difference being that the severalcolumns of fluid in the arrangement of Fig. 13 flow in generally spiraldirection radially of the rotor, as indicated by arrows 242, instead ofgenerally helically of thevlength of the rotor as in the construction ofFig. 8.

In the present embodiment the structure provides an inlet duct 244 forfluid, such as combustion gases, this duct having an annular portion 246for distributing the gas to the radially outermost grooves. The casingwall 218 carries baffles 248 provided with fingers 250 extending intogrooves 210 and box like cover members 252, similar to the cover members234 carried by the end wall 220. The arrangement of these baflles andcover members is similar to thatof the structure shown in Fig, 13 andneed not be described in detail, the dif ference between the arrangementat the two sides of the disc 202 being that in one case the fluid flowis in generally outward direction while in the other case the flow isin. generally spiral inward direction to the outlet duct 254. As in theprevious embodiments, this arrangement provides for counter flow.Preferably, as described, the fluid to be heated, which exands, flowsoutwardly, while the heating fluid which contracts due to being cooled,flows inwardly.

It will be evident that in the embodiment just described, thearrangement of the baflles and the cover members may be made so as toprovide flow of fluid counter to the direction of rotation of the rotorin as many of the sectors as is desired in order to provide the desiredrate of flow. Variation in relative size of inlet and outlet ports andthe provision of auxiliary guide fingers are, for the sakepof clarity,omitted from the figures. Other features of design previously describedmay equally well be applied to the embodiment under con sideration.

In all of the previously described embodiments, movement of the rotatingbody is utilized to induce flow of the fluid or fluids and the rotarymovement of the fluid and solid bodies is concurrent.

However, the basic principles of the invention are equally applicable,with improved results, in cases where in order to secure an even higherrate of heat transfer between fluid and solid bodies, the fluid isforced by mechanical means such as a fan to flow counter to thedirection of rotation of the solid body. For such a method of operation,it is evident that the structures hereinbefore described, except for themodifications illustrated in Figs. 5, 7 and 11, are suitable withoutchange, it only being required that appropriate fan or equivalent meansof any desired conventional kind be provided to effect the necessaryflow of fluid in the direction opposite that indicated by the arrows inthe several figures.

Even the modifications of Figs. 5, 7 and 11 would be operative withforced flow counter to the direction of rotation of the solid body, butin such cases the reversal of flow at intermediate places effected bythese structures would serve no useful purpose and would in fact bedetrimental.

superficially, it might appear that forced flow counter to the directionof rotation of the solid body is at variance with the basic principlesof the invention as hereinbefore described, but such is not the case,since high relative velocities between the heat exchanging bodies may besecured with relatively low absolute velocities of the fluid bodies. Lowabsolute velocity of the fluid avoids creating the undesirable turbulentrotary flow of the fluid in the plane of rotation hereinbeforediscussed, even though the relative velocity between the fluid and solidbodies is high. This, together with the fact that only relatively lowabsolute velocity of the fluid must be generated, insures a relativelyvery low power requirement for the rate of heat exchange obtained.

While for purposes of explaining the invention, apparatus has been shownfor heat exchange between two gaseous fluids both of which are caused toflow in accordance with the novel principles of the invention, it willbe understood that such principles are equally applicable for heatexchange between gaseous and liquid fluids, be-

c tween different liquids, and for heat transfer between a fluid and asolid body. Further, it will be apparent that if desired one of the twofluids between which heat is exchanged may flow in conventional fashionin heat exchange relation with the solid body which may have plainsurface or extended surface of known kind in heat exchange with suchfluid. a

It is accordingly to be understood that within the scope of theinvention many variations in design and arrangement are possible andthat certain features herein disjclosed may be used to the exclusion ofothers, the in vention being definedby and including all apparatuswithin the purview of the appended claims.

What is claimed: V 1. Heat exchange apparatus comprising a rotor havinga plurality of transverse parallel ribs providing a multiplicityof openperipherally continuous circulargroovelike channels, concentric with theaxis of rotation of the rotor for flow of fluid in paths of flow in saidchan nels lying in planes normal to said axis and stationary structureincluding inletand outlet openings for fluid and having a wallconcentric with and cooperating with said rotor to provide for flow ofsaid fluid between said openings through said channels inheat exchangerelation with the rotor, said structure including longitudinal baflies,each balfle having onelongitudinal edge abutting said wall and theopposite longitudinal edge having fingers extending into and obstructingsaid channels, longitudinally extending cover means for said channelsdisposed between adjacent said bafiles, means forming transfer pas: r

sages connecting different channels at' places adjacentlto sai'dbaflcles and at opposite sides of said cover means for new offiuidprogressively through different channels and means to drive said rotor.

2. Heat exchange apparatus comprising a rotor having a pluralityoftransverse parallel ribs providing a multiplicity of open peripherallycontinuous circular groovelike channels concentric with the axisofrotation of the rotor for flow of fluid in paths of flow in saidchannels lying in planes normal to said axis and stationary struetureincluding inlet and outlet openings for fluid and having a wallconcentric with and cooperating with'said rotor to provide for flow ofsaid fluid between said open ings through said channels inheat exchangerelation with said rotor, said structure including a plurality ofperipherally spaced longitudinal balfles, each baflle having onelongitudinal edge abutting said wall and the opposite longitudinal edgehaving fingers extending into and obstructing said channels to provide aplurality of channel sections in each channel, longitudinally extendingcover meahs fors a'id channels disposed peripherally between adjacentbaflles, means forming transfer passages connecting different sectionsof diiierent channelsjat places adjacent to said balfles and at oppositesides of said cover means for new of fluid progressively throughsections of different channels and means to drive said rotor.

3. Heat exchange apparatus comprising a rotor having a "plurality oftransverse parallel ribs providing a multiplicity of op'en peripherallycontinuous circular groovelike channels concentric withthe axis ofrotationof the rotor for flow of fluid in paths of flow in said channelslying in planes normal to said axis and stationary structure includinginlet and outlet openings for fluid and having a wall concentric withand cooperating with said rotor to provide for flow of said fluidbetween said openings through said channels in heat exchange relationwith the rotor, said structure including longitudinal baffle members,each baifle member having one longitudinal edge abutting said Wall andthe opposite longitudinal edge having a series of axial aligned fingersproviding bafiles extending into and obstructing a series of saidchannels, longitudinally extending cover means for said channelsdisposed peripherally between and peripherally spaced from adjacentbaflies to provide ports communicating with the channels adjacent thebaflles, means forming transfer passages defined in part by said covermeans, connecting ports with diflierent channels at opposite sides ofsaid cover means for flow of fluid progressively through the severalchannels and means to drive said rotor.

4. Heat exchange apparatus comprising a rotor having a plurality oftransverse parallel ribs providing a multiplicity of open peripherallycontinuous circular groovelike channels concentric with the axis ofrotation of the rotor for flow of fluid in paths of flow in saidchannels lying in planes normal to said axis and stationarystruceerie-r6 ture including inlet an outlet opening; forfluid and ing awall concentric with and coeperating with said ro' tor to provide forflow or said fluid between said openings through said channels in heatexchange relation with the rotor, said structure including a pluralityof longitudinally peripherally spaced baifles, each bane liav ing onelongitudinal edge abutting said wall and the op: posite, longitudinaledge having axially aligned fingers providing baflles extending into andobstructing said chan: nels, longitudinally extending cover means forsaid chan nels disposed peripherally between and peripherally spacedfrom adjacent baflles to provide ports communi catingwith the channelsadjacent the baflles, means including said cover means and partitionsdisposed oblique: ly with respect to the planes of the channels formingoblique transfer passages connecting ports communicating with certainofsaid channels at oneside of said cov er means with ports communicatingwith other channels at the other side of said cover means and :means todrive saidrotor. H U...

5 Heat exchange apparatus comprising a rotor having a plurality oftransverse parallel ribs providing a multiplicity of open peripherallycontinuous circular groovelikechannels concentric with the axis ofrotation of the rotor for flow of fluid in paths of flow in saidchannels lying in planes normal to said axis and stationary structureincluding inlet and outlet openings for fluid and having a wallconcentric with and cooperating with said rotor to provide for flow ofsaid fluid between said openings through said channels inheat exchangerelation with said rotor, said structure including a plurality oflongitudinal peripherally spaced sets of baffles, said baffle having onelongitudinal edge abutting said wall and the opposite longitudinal edgehaving fingers extending into and obstructing said channels, the bafllesof one set being peripherally offset with respect to the baflies of theadjacent sets, longitudinally extending cover means for said channel'sdisposed peripherally between andperipherally spaced from adjacentbattles of each set to provide port's communicating with the channelsadjacent the baflies, means forming transfer passages connecting portscorn municating with different channels at opposite sides of 'said covermeans for .flow of fluid progressively through dilfe'rent channels andmeans to drive said rotor.

6. Heat exchange apparatus comprising a rotor having a plurality oftransverse parallel ribs providing a multiplicity of open peripherallycontinuous circular groove-hire channels concentric with the axis ofrotation of the rotor for flow of fluidin paths of flow in said channelslying in planes normal to said axis and stationary structure includinginlet and outlet openings for fluid and having a wall concentric withand cooperating with said rotor to provide for flow of said fluidbetween said opening through said channels in heat exchange relationwith said rotor, said structure including a plurality of longitudinalperipherally spaced sets of bafiles, said baffies having onelongitudinal edge abutting said wall and the opposite longitudinal edgehaving fingers extending into and obstructing said channels, the bafflesof one set being peripherally olfset with respect to the baflles of theadjacent sets, longitudinally extending cover means for said channelsdisposed peripherally between and peripherally spaced from adjacentbaflles of each set' to provide ports communicating with the channelsadjacent the baflles, means forming transfer passages connecting portscommunicating with diflerent channels at opposite sides of said covermeans for flow of fluid progressively through diflerent channels, atleast certain of said transfer passages connecting ports situated aheadof said battles with ports situated behind adjacent baflles, consideredin the direction of rotation of the rotor and means to drive said rotor.

7. Heat exchange apparatus comprising a rotor having a wall and aplurality of transverse ribs extending from the opposite sides of saidwall to provide on each side. of the wall a series of peripherallyvcontinuous open groove-like circular channels concentric with the axisof rotation of the rotor, stationary means including inlet and outletopenings for fluid and having walls concentric with and cooperating withsaid rotor to provide for flow of fluid in paths of flow in saidchannels between said openings lying in planes normal to said axis, saidstationary means including longitudinal baflles, certain of said baflleshaving one longitudinal edge abutting one of said last named walls andthe other of said baflles having one longitudinal edge abutting theother of said last named walls and the opposite longitudinal edges ofsaid baflles having fingers extending into and obstructing saidchannels, longitudinally extending cover means for said channelsdisposed between adjacent bafiles, means forming transfer passagesconnecting difierent channels at places adjacent to said baflles and atopposite sides of said cover means for flow of fluid progressivelythrough different channels on each side of said first named wall andmeans to drive said rotor.

8. Heat exchange apparatus comprising a rotor hav ing a wall and aplurality of transverse ribs extending from the opposite sides of saidwall to provide on each side of the wall a series of peripherallycontinuous open groove-like circular channels concentric with the axisof rotation of the rotor, stationary means including inlet and outletopenings for fluid and having walls concentric with and cooperating withsaid rotor to provide for flow of fluid in paths of flow in saidchannels between said openings lying in planes normal to said axis, saidstationary means including a plurality of longitudinal peripherallyspaced baffles, certain of said baffles having one longitudinal edgeabutting one of said last named walls and the other of said bafiieshaving one longitudinal edge abutting the other of said last named wallsand the opposite longitudinal edges of said baflies having fingersextending into and obstructing each of said channels to divide the sameinto a plurality of sections, longitudinally extending cover means forsaid channels disposed between adjacent baflles, means forming transferpassages connecting different sections of said channels at placesadjacent to said bafiles and at opposite sides of said cover means forflow of fluid in each side of said first named wall progressivelythrough peripherally displaced sections of diflerent channels on thesame side of said first named wall and means to drive said rotor.

9. Heat exchange apparatus comprising a rotor drum having a plurality oftransverse open circular groovelike channels concentric with the axis ofrotation of the drum and providing for flow of fluid in paths of flow 12in said channels lying in planes normally to said axis, said channelscomprising a first series of inner channels extending radially inwardlyfrom the wall of the drum and a second series of outer channelsextending radially outwardly from the wall of the drum with said walldefining the bottoms of both series of channels, stationary structureincluding inlet and outlet openings for fluid and having inner and outerwalls concentric with and cooperating with said drum to provide for flowof fluid in paths of flow in said inner and outer channels between saidopenings, said stationary structure including longitudinal inner andouter bafiles, said inner baflles having one longitudinal edge abuttingsaid inner wall and the opposite longitudinal edge having fingersextending into and obstructing said inner channels, said outer baflleshaving one longitudinal edge abutting said outer wall and the oppositelongitudinal edge having fingers extending into and obstructing saidouter channels, longitudinally extending inner and outer cover membersfor said inner and outer channels disposed between adjacent innerbaffles and between adjacent outer baflles,

means providing inner transfer passages connecting different innerchannels at places adjacent said inner batfles at opposite sides of saidinner cover means for flow of a first fluid medium progressively throughdifferent channels of said first series, means providing outer transferpassages connecting dilferent outer channels at places adjacent saidouter baflles at opposite sides of said outer cover means for flow of asecond fluid medium progressively through difierent channels of saidsecond series and means to drive said rotor drum.

10. A structure as defined in claim 9 in which said transfer passagesare arranged for flow of each of the fluids from channel to channelprogressively of the length of the drum and in countercurrent relationwith respect to each other lengthwise of the drum.

References Cited in the file of this patent UNITED STATES PATENTS1,639,051 Munday Aug. 16, 1927 1,698,313 Luther Jan. 8, 1929 21,897,613Jensen Feb.-14, 1933 1,914,084 Ellis et al. June 13, 1933 2,369,993Turner Feb. 20, 1945 2,402,307 Vannerus June 18, 1946 V FOREIGN PATENTS252,373 Great Britain Apr. 14, 1927 500,389 Great Britain Feb. 8, 1939545,782 Germany Mar. 5, 1932

